The Acropolis is the obvious one and deserves an early start, but Athens pays you back for walking between its museums rather than taxiing past them.
The Acropolis and the Parthenon
The rock above the city, carrying the Parthenon, the Erechtheion and the small temple of Athena Nike. Go at opening or in the last two hours: there is almost no shade on the summit and summer queues are long.
Acropolis Museum
Dionysiou Areopagitou 15, at the foot of the rock; 20 euro full price. April to October it opens Tue-Sun 9:00-20:00, Mondays to 17:00 and Fridays to 22:00, with shorter winter hours. The glass-walled top floor holds the Parthenon frieze at eye level.
National Archaeological Museum
44 Patission Street, about 25 minutes' walk north of Syntagma; 20 euro. In the summer season it runs Wed-Mon 8:00-20:00 and Tue 13:00-20:00. Mycenaean gold, Cycladic figurines and the Antikythera mechanism are all here.
Panathenaic Stadium
The all-marble stadium that hosted the first modern Olympics in 1896, open daily 8:00-19:00. Conservation work on the marble kept the running track itself closed to visitors into September 2026, so check first if walking it is the point.
Stavros Niarchos Foundation Cultural Center
Renzo Piano's complex south of the centre towards the coast, holding the National Library and the Greek National Opera under a sloping public park. The grounds are free to walk and there is a steady free events programme; reach it by city bus or tram rather than on foot.